<boily> le/rn \xc3\xbc/\xc3\xbc is the ridiculously happy derivative of the letter \xe2\x80\x98u\xe2\x80\x99 with respect to time.

|a+b@| = { √(a²-b²) if a²-b² ≥ 0 ; i√(a²-b²) if a²-b² < 0 }